Police and firemen evacuated nearly 100 civil servants and 16 detained illegal immigrants from offices at the Central Government Pier when a rusty drum on a Marine Department launch began leaking what appeared to be toxic fumes.

The pier area was sealed off shortly after 3pm while a government chemist examined the drum.

Firemen sprayed water over the fumes, later found to be either sulphur or phosphorous, a government spokesman said.

The drum, believed to have fallen off a ship some time ago, was picked up by a Marine Department launch near Shek O beach yesterday.

After berthing alongside the Central pier, the master of the launch discovered the leakage and officers of the Fire Services, Customs and Excise and Immigration departments were forced to leave the building.